Yeah, this is kind of the bad news for straight guys but...what Lee M says demonstrates the most crucial point: no amount of training is really going to do any good if the person isn't seriously into it. You gotta get kind of obsessive about cock because ultimately, just taking the cock down isn't the true satisfaction for the man getting sucked. It's taking it down over and over, keeping it down for as long as you can, letting him enjoy being holstered to the balls with some regularity.

And with skullfucking, I should have stated in the first post that this is really a variation of rough sex...so you gotta find someone who enjoys being used. And there are PLENTY of people out there who do like being used. You can find them by exploring the SM/kink/fetish communities.